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Must-know: An investor's guide to off-shore driller Noble Corp.

Part 3
Must-know: An investor's guide to off-shore driller Noble Corp. (Part 3 of 9)

Why Noble Corp.’s fleet structure is crucial to its business

An overview of Noble’s fleet

Like many of its competitors, Noble possesses a diversified fleet of rigs that are best suited to different situations and environments. The unique characteristics and limitations of the ship types make rig substitution difficult and unlikely. Across the industry, the average life expectancy of a newly constructed rig is about 25 years, but it’s not uncommon for companies to rebuild and renovate rigs that are still in good condition at the end of the expected life span. Upon the completion of ship reconstruction, the ship is once again considered a new ship in company records. Taking into account rig reconstruction, Noble’s average rig age is 12.11 years.

Rig Types

Drillship

 

DrillshipEnlarge Graph

Noble has 14 drillships in its fleet. This rig closely resembles a normal ship in both shape and maneuverability, making it the easiest rig to transport between contracts. Drillships’ cargo capacity is significantly greater than other rigs’, making them suitable for operations hundreds of miles from shore for weeks at a time. However, their shape also makes them the least stable of all of the rig types. This limits drillships to environments with calmer waters.

Semi-submersible

SemisubmersibleEnlarge Graph

Noble has 14 semi-submersibles in its fleet. This rig can partially submerge its hull to provide greater stability as the ship drills into the ocean floor. Some semi-submersibles can propel themselves, while others need assistance from tugboats to move between drilling sites. Because of their more rectangular shape and submerging abilities, they’re more suited to operations in rougher waters and harsher climates than drillships.

Jackup

JackupEnlarge Graph

Noble has 49 jackups in its fleet. These are also mobile platforms, but they differentiate themselves by their legs, which lower to the ocean floor to provide stable support for drilling and act as a foundation for the rig itself. Because of the need to touch the ocean floor, jackup rigs are typically used in cases where water depths are 400 feet or less, but even jackups are capable of drilling as far as 35,000 feet below the surface.

Rigs also have many sub-types and specializations 

In addition to the rig types, rigs can be classified based on depth and environmental capabilities.

  • Ultra-deepwater: Capable of drilling in water depths of 7,500 feet and greater. This classification can be given to semi-submersibles and drillships.
  • Deepwater: Capable of drilling in water depths of up to 7,500 feet. This classification can be given to semi-submersibles and drillships.
  • Midwater: Capable of drilling in water depths of up to 4,000 feet. This classification can be given to semi-submersibles and drillships.
  • High specification: This classification can be given to jackups. Compared to a regular jackup, a high-specification jackup has slightly deeper drilling abilities, more powerful machinery, and greater storage capacity.
  • Harsh environment: Rigs with harsh environment capabilities have better stabilization systems and more usable deck space. Harsh environment drillships and semi-submersibles also have displacement that’s better suited to stability in rough waters.

To learn about comparable fleets, see Why Rowan Companies offers a leading quality fleet.

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